This article was originally published in 2013. The photos in this article differ from the original article.
Most mornings, I go into my garden early and hand-pollinate my zucchini using a tiny paintbrush. Despite the overall decline of honey bees due to Colony Collapse Disorder, there are actually many of them in my garden, thanks to a neighbor with a carefully tended hive. Why aren’t these bees doing their job? It’s because while honey bees can pollinate squash, they aren’t very good at it. The best pollinator for squash, aptly named the squash bee, is native to the Americas, but seems to be missing in action. Dwindling native bee habitat keeps many gardeners in the Bay Area and well beyond hand-pollinating their squash.
While the European honey bee is the species most commonly used in agriculture, recent scientific studies have shown the benefits of native bees to agriculture in Contra Costa County and elsewhere. Many times, native bees are actually more efficient than honey bees at pollinating certain crops. Natives like Orchard bees are managed commercially to pollinate apples and other fruit, and alkali bees are used to pollinate vast alfalfa fields. Not to mention a tomato plant’s best friend, the native bumble bee, which buzz pollinates tomatoes by shaking pollen loose from blossoms with its flight muscles: a feat honey bees can’t accomplish!
Much is still to be discovered about native bees and their relationships with plants, but we do know that 75% of all flowering plants depend on animal pollinators – mostly bees. This includes native plants that provide berries and seeds for birds and other wildlife, as well as garden and agricultural crops. Research through UC Berkeley, San Francisco State, UC Davis, and the Cal Academy of Sciences is showing that we have an incredibly diverse population of native bees (about 1,600 species in California), but that diversity is declining. Some species recorded historically are no longer found.
We can all help both native bees and honey bees. Plant bee-attractive plants, especially native species, in dense patches 4 – 5 feet wide. Extend the season of bloom, if possible, with plants that flower at different times of the year. Salvias, lavender, Ceanothus, California native buckwheats (Eriogonum sp.), California poppies, and many species from the aster/sunflower family are all good choices. Don’t use pesticides, which have been implicated in Colony Collapse Disorder. If you have a birdbath, add rocks or pebbles so bees can make a safe exit. Leave some unmanaged or natural areas in your landscape for nesting habitat; bees need cavities in old wood and undisturbed and unmulched soil. Observing and enjoying bees in your garden are great ways to appreciate and preserve some of the intricate natural interrelationships in our watersheds.